Sequential circuits samplers

I just received this yesterday only to find one of the voices are dead.  Everything else works fine.  I swapped filter chips between a working voice and the dead one and had no success.  

So it appears to be something more serious.  Anyone know what the next step is for determining the cause?  I am not technical enough to fix this myself, so if it's going to require an expensive investigation by a tech, I may have to just send it back for a refund.  

(Also, does anyone know how to calibrate the filters?  Mine are somewhat all over the place and there are no trimmers inside to tweak. I assume a service manual might explain this?)

Thanks!